Hydro-hoist



F. B. SMIGHT.

HYDRO HOIST.

APPLICATION FILED AUG-11,1917. RENEWED FEB. 12. I919.

1,374,888. Patented Apr. 12, 1921.

11 bio/ 116 6.

F. B. SMIGHT.

HYDRO HOIST.

RENEWED FEB. 12.1919.

APPLICATION FILED AUG-11,1917.

Patented Apr. 12, 1921.

3 SHEETSSHEET 2- IIIIIM F. B. SMIGHT.

HYDRO HOIST.

APPLICATION FILED AUG-1111917. RENEWED FEB. 12, 1919. 1,374,888.

Patented Apr. 12, 1921. X a SHEETSSHEET s 47 W e a v w i v. .7 1 d .5? O r r 7/ u w N B m i; 4 Q mx Q i T q 5% 8 T -L, 1/ z 0 mull 8 E Q Q Q H 0 $13 H UNITED STATES PATENT OFFICE.

FRANK B. SMIGHT, OF MILWAUKEE, WISCONSIN, ASSIGNOB, BY KESNE ASSIGN- MENTS, TO HYDRO-H0181 COMPANY, 01 MILWAUKEE, WISCONSIN, A CORPORA- TION OF WISCONSIN.

HYDRO-H0181;

Specification of Letters 1'atent.

Application filed August 11, 1917, Serial No. 185,722. Renewed February 12, 1919. Serial No. 276,602.

To all to lwm it may concern Be it known that I, FRANK B. SMIGHT, a citizen of the United States, resldin at Milwaukee, county of Milwaukee, and tate of Wisconsin, have invented new and useful Improvements in Hydro-Hoists, of which the following is a specification.

My invention relates to improvements in dumping devices for vehicles. The object of my invention is to provide a more reliable andsimple device for raising the front end of a vehicle box or body, whereby the contents of such box or body will be delivered rearwardly and discharged therefrom, and said invention will be more fully described by reference to the accompanying drawings, in which Figure 1 represents a side view, part broken away to better disclose the construction of the same.

Fig. 2 is an end view, part broken away.

Fig. 3 is a detail, and

Fig. 4 is a vertical section.

Like parts are identified by the same reference numerals throughout the several views.

1 is the box or body of the vehicle, which is pivotally supported at its respective sides from near its rear end from the frame 2 by brackets 3, 3 and pivots 4, 4. The box or body 1 is adapted to be raised, and held while up, and lowered by the action of the pistons 4:, 4 operating in the cylinders 5, 5. The pistons 4', 4 are respectively connected to the box or body 1 by piston rods 6, 6, trunnions 7, 7 and brackets 8, 8, whereby as said pistons are raised the front end of said box. or body is raised, and vice versa as said pistons are moved downwardly said box or body will also be brou ht back to its normal position. The cylin ers 5, 5 are each pivotally connected with the vehicle frame members 2, 2 by brackets 11,

'11, and trunnions 12, 12. The cylinders are therefore adapted to swing or tilt about the axes of these trunnions 12 when the vehicle box or body is being raised or lowered.

A rotary pump is mounted in close proximity to these trunnion axes and swings in a short arc with the cylinders, and the liquid supply and delivery connections between the pumpand the cylinders are all formed as a single tilting unit. The cylinders 5 are provided with a supply of 01]. or other non-freezing liquid, and when it is desired to tilt the box or body to dumping position, the operator, by pressing upon a foot pedal 13, connects up the vehicle motor with the rotary pump 15, as hereinafter described, and t e pump is then operated by the motor to draw the oil or other liquid from the portion of the cylinders 5 above the pistons 4 thereln, and deliver it to the lower end portions of the cylinders underneath the pistons the pump delivering the liquid under suiiicient pressure to raise the pistons, piston rods and the front end of the box or body, thereby tilting the latter upon the pivot shaft or trunnions 4 to the dumping position indicated by dotted lines in Fig. 1. By providing means for limiting the supply of liquid to the pump, the lifting movement will cease with the cessation of liquid delivery from the pump, although the pump may continue in motion. The box or body will, however, be held in dumping position by the liquid column in the respective cylinders underneath the istons, until the operator opens a valved by-pass to allow the liquid to return from the lower portions of the respective cylinders to the upper ortions thereof, under pressure of the oad upon the pistons as exerted by the body or box of the vehicle.

It will be observed that the connections of the rotary pump 15 are such that when this pump is being operated, liquid may be supplied to it from the upper portion'of each cylinder 5, through the cylinder ports 19 and the ducts 16, which constitute the pump supply or inlet ducts. The pump delivers this liquid into a pair of horizontal ducts 18, and through downwardly extending ducts 17 leading to the respective jack cylinders 5 at or near their lower ends, and below the lowest point reached by the pistons 4'. The pistons will therefore be lifted simultaneously in the respective jack cylinders, and, of course, with equal pressure. The upward piston movement will continue until these pistons reach and close the ports 19. Thereupon, the liquid supply to the ump will be out off, the piston having su cient width or thickness to effectively close the ports 19 for a period long enough to allow the movement to cease, notwithstanding the fact that a small quantity of liquid may be the ports 19 have been closed. There will ordinarily be suflicient air or vapor in the system to relieve any vacuum that might otherwise be produced in these ducts by this action of the pump. The ducts 16, however, are quite small, and therefore do not contain enough liquid to supply the pump for any material length of time after the ports 19 have been closed. But the pump may continue in operation without additional liquid supply, and the columns of liquid below the pistons in the jack cylinders will be maintained with the liquid in static condition, thus supporting the box or body in its dotted line position, as shown in Fig. 1.

Each of the ducts 16 is provided with a by-pass or branch duct 20 leading to the associated cylinder 5 above its port 19. These by-pass ducts are provided with check valves 48, ball valves being preferably used, and arranged to seat by gravity in the upwardly extending portions of the ducts 20, whereby flow of liquid through these ducts from the cylinders is prevented, but a re-.

verse flow or delivery of liquid to the cyline ders is permitted.

A by-pass duct 22 cross connects the ducts 18 with the ducts 16 in proximity to the pump outlet and inlet, respectively. A valve 24, provided with a port 21, is employed to control the flow of liquid through this by-pass 22. The valve 24 is preferably a rotary valve, and the port 21 extends through it. It is provided with a stem 27 to which an operating arm 26 is attached, whereby the valve may be opened or closed by swinging the arm 26 to bring the port 21 into or out of registry with the by-pass duct 22. The valve 24 may be manually opened from the drivers seat by providing a foot pedal 23, connected with the arm 26 by a rod 25. This valve 24 will, however,

be closed when the vehicle box or body is being raised, as above described. But whenever the operator desires to allow the parts to return to normal position, he depresses the foot pedal 23, and opens the valve 24. The weight of the vehicle box and associated parts will thereupon be effective to force the pistons downwardly, driving the liquid 1 from beneath them upwardly through the ducts 17 and by-pass 22 into the ducts 16, and thence through the branches or bypasses 20 into the upper ends ofthe cylinders.

The arrangement of the valve 24 and its operating connections is such that its axis coincides with the axes of the cylinder trunnions 12, and therefore the valve 24 may be held in a relatively stationary position, although the cylinders are tilted to maintain alinement with the piston rods while the vehicle box is descending, and as the box approaches its normal horizontal position, this tilting movement of the cylinders upon their supporting trunnions carries with it the casing or seating of the valve 24, and progressively closes the valve port 21 until the port becomes substantially closed during the final downward movement of the box. By thus progressively closing the valve port 21-, the flow of liquid from beneath the pistons is retarded in such a manner as to prevent any injurious or annoying shock, which would be caused if the box dropped violently upon its supporting frame members. The pump is connected up with the vehicle motor as follows:

Ordinary transmission mechanism located in the casing 30 is provided with a driven shaft 31 loosely coupled end to end with a shaft 34 by a coupling pin 32 and member 33. A clutch at 35 operatively connects this shaft with a sprocket wheel 36, which drives the pump through a sprocket chain 37 sprocket wheel 38, shaft 39 and flexibly jointed shaft 40, the latter being adapted to accommodate itself to the movements of the pump during the tiltin movements of the cylinders, as above described. The movements of the pump, in accordance with the tilting movement of the cylinders, are slight, owing to the proximity of the pump to the axes of the cylinder trunnions 12. The shifting member of the clutch 35 is operated by an ordinary shifting lever, operatively connected to the foot pedal 13 by the rod 14. Both of the foot pedals 13 and 23 are spring retracted pedals of ordinary construction.

Owing to the fact that the cylinder supporting trunnions 12 are located near the upper ends of the cylinders, the arc in which the upper ends of the cylinders swing, is necessarily short, inasmuch as the piston rods are pivotally connected with the body at their upper ends. Since the pistons are at the lower ends of the cylinders when the body lifting movement commences. the cylinders and piston rods are easily kept in perfect alinement without cramping effects, and particularly so during the period of greatest strain, 2'. 8., during the initial portion of the lifting movement, whereas if the cylinders were pivoted to the sub-frame of the vehicle, midway of their ends. (as has heretofore been the general practice), the distance between the pivotal axes of the cylinders, and those of the pivotal connec tions of the piston rods with the vehicle body, would be such as to set up much greater stresses, due to the longer are of movement and the increased actual distance.

The cramping effects or pressure of the piston rods in the cap hearings or boxes at the upper ends of the cylinders, are therefore greatly reduced by locating the trunnions 12 near the tops of the cylinders. In my improved construction, a relatively slight movement of the upper ends of the cylinders keeps their axes in perfect alincmcnt with the piston rods during all stages of the movement.

A reservoir 41, one for each cylinder 5, is employed to maintain a supply of liquid to such cylinder, and is connected with the upper end thereof by a duct or port 42. Each reservoir is secured to its associated cylinder head or cap, and therefore swings with the cylinder during the tilting movements above described.

The reservoirs 41 are each provided with a filling aperture normally closed by a plug 43, and located in a shouldered portion 44, below the top of the reservoir, whereby air will be pocketed in the upper portion of the reservoir, and allow the liquid contents to flow freely to the cylinders without producing a vacuum in the reservoir, such as might otherwise prevent liquid delivery.

Air is free to pass into the cylinders 5 through the ports 47, the hollow piston rods, and ports 46 in the lower ends of these rods. Therefore, when the pump is in operation to lift the pistons, no vacuum will be produced in the upper portions of the cylinders, since air is free to enter through the hollow piston rods. On the other hand, when the pistons 4' move downwardly, this air will not act as a resisting cushion, but will pass freely out of the hollow piston rods as the liquid in the cylinders 5 enters the rods through the ports 46. Any air within the cylinder will, of course, rise through the liquid therein, and pass to the upper portion of the associated reservoir 41.

Briefly reviewing the operation of my improved dumping apparatus, and assuming the parts to be in the normal position, the operator, without leaving his seat, may dump the contents of the box or body 1 by merely pressing upon the foot treadle 13 to connect up the clutch 35, and utilize the power of the motor to operate the pump. When the box reaches the tilted position indicated by dotted lines in Fig. 1, the supply of liquid to the pump will be automatically cut off, for the reason that the pistons 4 will then have moved to a position where they cover the ports 19. The ball valves 48 prevent the liquid from being drawn from above the pistons through the bypasses 20. The pump may therefore continue in operation without lifting the box beyond its proper dumping position, and without danger of injuring any of the connections or of forcing the pistons against the upper cylinder caps.

After the dumping operation has been completed, the operator then depresses the foot treadle 13 to open the by-pass valve 4 24, whereupon the box will descend by gravity from the dotted line to the full line position, and during its final movement in this direction, its motion will be checked, as above described, by the tilting of the cylinders 5 and the casing of valve 24 about the relatively stationary valve to progres,

sively close the port 21, and retard the flow of liquid therethrough, in a manner to virtually bring the box to rest before it strikes 1tlhe supporting frame members of the veicle.

Having thus described my invention what I claim as new and desire to secure by Letters Patent, is

1. In a device of the described class, the combination with a movable vehicle and a single box pivotally connected near its rear end to said vehicle, a pair of cylinders pivotally connected near their upper ends to the frame of said vehicle, a pair of pistons located in said cylinders, a pair of hollow piston rods respectively connected at one end with said pistons and extending therefrom through the upper ends of said cylinders and pivotally connected with said single box, atransmission, a pump, and ducts leading from said pump to said cylinders both above and below said pistons, and means for connecting said motor and pump, whereby said pistons are moved in said cylinders, and whereby said box is adapted to be raised at its front end and its contents discharged. 2. The combination in a vehicle, of a tiltmg body, a pump, a pair of cylinders below said body, a air of pistons in said cylinders, a pair 0 hollow piston rods connected with said pistons, means for stopping the upward movement of the pistons temporarily, said pistons being adapted as .they move upwardly to close the outlet ports of the inclosing cylinders, whereby the flow of oil from said cylinders to said pump is cut off, and said pistons are automatically stopped for a brief period, check valves located above the pistons when raised, said check valves being adapted to be opened by the pressure of oil or other liquid from the pump, whereby the movement of said pistons are allowed to reverse and the ports leading to the spaces above the pistons are opened when said pistons move downwardly at their normal speed.

3. In a device of the described class, the combination with a movable vehicle, a single box pivotally connected near its rear end to said vehicle, a pairof cylinders pivotally connected near their upper ends to the frame of said vehicle, a pair of pistons respectively located in said cylinders respectively, a pair of hollow piston rods respectively connected at one end with said pistons and extending therefrom through the upper ends of said cylinders, an opening formed in the lower end of said rods, whereby oil or other liquid can enter said rods from the inclosing cylinder, a duct leading from the upper end of said hollow piston rods for the escape of air as said hollow rods are filled with liquid, said rods being pivotally connected with said sin le box, a transmission, a pump, ducts lea ing from said ump to said cylinders both above and below said pistons, and means for connecting said motor and pump, whereby said pistons are moved in said cylinders, and whereby said box is adapted to be raised at its front end and its contents discharged.

4. The combination of a vehicle, a tilting body, a ump, and a pair of cylinders mounted elow said body, saidcylinders being tiltingly mounted at their upper ends, hollow piston rods pivotally connected to said body, and means for operating all of said parts.

5. The combination of a vehicle, a tilting body, a pump, a cylinder mounted below said body, means actuated by the inclination of said cylinder for automatically checking the downward movement of said body, and means for operating said mechanism.

6. In a device of the described class, the combination with a movable vehicle, a single box ivotally connected near its rear end to said vehicle, a pair of cylinders pivotally connected near their upper ends to the frame of said vehicle, a pair of pistons respectively located in said cylinders respectively, a pair of hollow piston rods respectively connected at one end with said pistons and extending therefrom through the upper ends of said cylinders and pivotally connected with said single box, a reservoir for each cylinder, said reservoirsbeing adapted to supply oil for said cylinders as said pistons are raised, and to fill the additional space in said cylinders caused by the upward movement of said pistons and ducts leading from said reservoirs to said cylinders, a transmission, a pump, ducts leading from said pump to said cylinders both above and below said pistons, and means for connecting said motor, pump and cylinders whereby said pistons are moved in said cylinders, and whereby said box is adapted to be raised at its front end and its contents discharged.

7. The combination with a dumping car having a tilting body, of a power means for tilting said body, comprising a hydraulic jack including a cylinder and a piston, said jack cylinder and piston operatively connected to the car and the body to tilt said body, a pump having its inlet and outlet openings connected respectively to the cylinder on opposite sides of the piston, said cylinder on opposite sides of the piston containing a fluid medium which is moved by the pump for moving the piston, and means for operating the pump, said piston being automatically stopped when it reaches a predetermined position of rest by the stopping of the supply of liquid medium to the pump without stopping the operation of the pump.

8. A dum ing car including the combination of a tiltlng body, a hydraulic jack cylinder and piston operatively connected to tilt the body, a pump having its inlet opening connected to the upper portion of the cylinder, and its outlet opening connected to the lower portion thereof, said cylinder on opposite sides of the piston containing a fluid medium, means for rotating the pump, and valve means for transposing the flow of fluid medium from the lower to the upper portion of the cylinder, the movement of said piston being automatically stopped when it reaches a predetermined position of rest by closing the inlet opening of the fluid medium to the pump without stopping the operation of the pump.

9. A dumping car, including the combination with non-tilting frame members, of a tilting body, a hydraulic jack pivoted to said frame members near its upper end, and operatively connected to lift and lower one end of the body, a pump located close to the pivot axis, and supported to swing with the jack, power connections adapted to drive the pum from the vehicle motor, means for supp ying power liquid to the pump from one portion of the jack to deliver it to another portion thereof to tilt the body, and piston controlled means for cutting off the liquid supply to the pump when the body has been raised to a predetermined degree of inclination. I

10. A dumping car, including the combination of relatively stationary frame members, a tilting body, a hydraulic jack'having a pivotal mounting on the frame members, and arranged to swing in conformity with the tilting movements of the body, a pump supported near the pivotal axis of the jack and arranged to swing with it, in a short arc about said axis, flexible power transmitting connections for driving the pump, said pump having supply ducts leading thereto from the upper portlon of the jack, and outlet lilucts leading to the lower portion of the ac 11. A fluid hoist, comprising a cylinder having ports at opposite end portions, a piston within the cylinder and between the ports and having a piston rod extending through the cylinder, and means for moving a fluid medium within the cylinder from one side of the piston to the other to move the piston to a position to close one of the ports, to automatically stop the movement of the fluid medium to the moving means and the movement of the piston without stopping the movement of the means for moving the fluid medium.

12. A. fluid hoist, comprising a cylinder having ports at opposite end portions, a piston within the cylinder and between the ports and having a piston rod extending through the cylinder, ducts connecting the two ports together, and a pump intersecting the ducts for moving a fluid medium within the cylinder from one side of the piston to piston within the cylinder and between the ports and having a piston rod extending through the cylinder, ducts connecting the two port/s together, a pump intersecting the ducts between the two ports for moving a fluid medium within the cylinder from one side of the piston to the other to move the piston to a position to close the port which is supplying the fluid medium to the pump and stop the passage of the fluid medium therethrough, to automatically stop the movement of the piston without stopping the operation of the pump, and a valve controlled duct in communication with the two port ducts on opposite sides of the pump to permit the passage of the fluid medium from one side of the piston to the other without passing through the pump.

14. A fluid hoist, comprising a cylinder having ports at opposite end portions, a piston within the cylinder and between the ports and having a piston rod extending through the cylinder, ducts connecting the two ports together, a power driven pump intersecting the ducts between the two ports for moving a fluid medium within the cylind'er from one side of the piston to the other to move the piston to a position to close the port which is supplying the fluid medium to the pump and stop vthe'passa ge of the medium therethrough, to automatically stop the movement of the piston without stopping the operation of the pump, said cylinder containing a larger quantity of fluid medium when the piston is in one of its positions of rest than when in another, means for receiving, holding and returning to the cylinder the at times surplus fluid medium, and means permitting the return of the fluid medium from one side of the piston to the opposite side thereof.

15. A fluid hoist, comprising a cylinder having ports at opposite end portions, a valveless piston within the cylinder and between the ports and having' a piston rod extending through the cylinder, ducts connecting the two ports together, a power driven pump intersecting the ducts between the two ports for moving a fluid medium within the cylinder from one side of the piston to the other to move the piston to a .position to close the port which is supplying the fluid medium to the pump to automatically stop the movement of the piston Without stopping the operation of the pump, said cylinder containing a larger quantity of fluid medium when the piston is in one of its positions of rest than when in another, a tank having an opening in free communication with the upper portion of the bore of the cylinder, and a valved means for permitting the return of the fluid medium from one side of the piston to the opposite side thereof. I

16. A fluid hoist, comprising a cylinder having ports at opposite end portions and a lead port in communication with one of the first mentioned ports and the cylinder, a piston within the cylinder and between the ports and having a piston rod extending through the cylinder, and means for moving a fluid medium within the cylinder from one side of the piston to the other to move the piston to a predetermined position of rest, said position of rest automatically stopping the movement of the fluid medium to the moving means and thereby automatically stop ing the movement of the piston.

17. A uid hoist, comprising a cylinder having ports at opposite end portions and a lead port in communication with one of the first mentioned ports and the cylinder, a piston within the cylinder and between the ports and having a piston rod extending through the cylinder, ducts connecting the two ports together, and a pump intersecting the ducts for moving a fluid medium within the cylinder from one side of the piston to the other to move the piston to a predetermined position of rest, said position of rest closing one of the cylinder ports and the passage of the fluid medium therethrough and thereby automatically stopping the movement of the piston.

18. A fluid hoist, comprising a cylinder having ports at opposite end" portions and a lead port in communicationwith one of the first mentioned ports and the cylinder, 8. piston within the cylinder and between the ports and having a piston rod extending through the cylinder, ducts connecting the two ports together, a pump intersecting the ducts between the two ports for moving a fluid medium within the cylinder from one side of the piston to the other to move the piston to a predetermined position of rest, said position of rest of the piston closing the port which 'is supplying the fluid medium therethrough and thereb automatically stopping the movement 0 the piston, and a valved controlled duct in communication" with the two port ducts on opposite sides of the pump to permit the passage of the fluid medium from one side of the iston to the other without passing throug the ump.

19. A fluid hoist, comprising a cylinder having ports at opposite end portions and a lead port in communication with one of the first mentioned ports and the cylinder, a check valve controlling said lead port. a piston within the cylinder and between the ports and having a piston rod extending through the cylinder, ducts connecting the two ports together, a ower driven pump intersecting the ducts etween the two ports for moving a fluid medium within the cylinder from one side of the piston to the other to move the piston to a predetermined position of rest, said position of rest of the piston closin the port which is supplying the fluid me ium to the pump and thereby automatically stopping the movement of the piston, said cylinder containing a larger quantity of fluid medium when the piston is in one of its positions of rest than when in another, means for receiving, holding and returning to the cylinder the at times surplus fluid medium, and means permitting the return of the fluid medium from one side of the piston to the opposite side thereof.

20. A fluid hoist, comprising a cylinder having ports at opposite end portions and a lead port in communication with one of the first mentioned ports and the cylinder, :1

check valve controlling said lead port, a piston within the cylinder and between the ports and having a piston rod extending through the cylinder, ducts connecting the two ports together, a power driven pump intersecting the ducts between the two ports for moving a fluid medium within the cylinder from one side of the piston to the other to move the piston to a predetermined position of rest, said position of rest of the piston closing the port which is supplying the fluid medium to the pump and thereby automatically stopping the movement of the piston, said cylinder containing a larger quantity of fluid medium when the piston is in one of its positions of rest than when in another, a tank having an opening in free communication with the bore of the cylinder, and a valved means for permitting the return of the fluid medium from one side of the piston to the opposite side thereof.

In testimony whereof I afiix my signature in the presence of two witnesses.

FRANK B. SMIGHT.

Witnesses:

JAS. B. ERWIN, O. C. WEBER. 

